Using possibilities of the Central Anatolian syenites as fluxing agent for producing the porcelain tiles

Porcelain stoneware tiles are inorganic products that have been used in recent years as covering materials for both interior and exterior applications. These products are mainly made from a mixture of clay, kaolin and alkali fluxes. Nepheline syenites are raw materials used for the production of ceramic tiles due to their high alumina and alkali content, low silica content and low viscosity. In this study, the possibilities of using some alkali sources, especially syenite and nepheline syenite, found in between the Kırşehir and Yozgat, and surroundings in Central Anatolia, in porcelain tile formulations from 10 % to 40 % were investigated. Syenites are known to consist mainly of K- and Na- feldspars and contain index minerals such as quartz and nepheline according to their silica saturation. In this study, chemical, mineralogical and petrographical analyses of syenites used in porcelain tile structures were carried out and their technological properties were determined by firing at porcelain tile firing temperatures with standard albite and alkali feldspar sources. On the basis of these data, the values of bulk density, firing shrinkage ( %), water absorption (%), breaking strength (N/mm²) and colour (L, a, b) of the porcelain tile bodies with 40 % inclusion in the porcelain tile body after firing were determined and their comparisons with standard porcelain tile bodies were made. In addition, the sintering behaviour of the tile bodies at different temperature conditions were investigated and the fired phase analysis was determined by XRD (X-ray diffractometer) and the microstructure of all bodies was investigated by SEM (scanning electron microscope). As a result, it was observed that some syenites in Yozgat, Kırşehir and its surroundings are good fluxing raw materials and have the potential to be used in porcelain tiles.